Child maltreatment is destructive to the psychological and biological development of children, significantly increasing their risk for mental health disorders throughout the lifespan. Thus, translational research which uses our knowledge of risk and protective factors, at multiple levels of analysis, to inform and evaluate evidence-based interventions for young maltreated children is sorely needed (Cicchetti & Valentino, 2006). Because child maltreatment is a pathogenic relational experience, often beginning during early childhood and in the context of the parent-child relationship, dyadic interventions that address the developmental needs of preschool-aged maltreated children and their parents are necessary. There is a significant gap, however, regarding the establishment of empirically supported treatments targeted toward both maltreated preschool- aged children and their parents, including the identification of the mechanisms underlying beneficial outcomes. Accordingly, the aims of this project are to evaluate (1) the efficacy of Reminiscing and Emotion Training (RET), a brief, dyadic intervention for maltreated preschool-aged children and their mothers, in fostering maltreated children's development in cognitive, emotional, and physiological domains and in improving their mothers' parenting; and (2) the specific mechanisms underlying intervention effects, including the role of child and maternal diurnal cortisol regulation. To accomplish these aims, the project will enroll 240 preschool-aged children and their mothers into a randomized clinical trial. Maltreating families will be randomized into one of two conditions: the RET condition, or a Community Standard condition (CS), which serves as an active control. Additionally a demographically matched group of nonmaltreating families will be included to determine the extent to which families in the RET group approximate functioning of nonmaltreated families over time. Key components of the RET include training mothers to (a) ask open-ended questions, (b) use detailed descriptions and build on children's responses, (c) make causal connections between children's experiences and emotions, and (d) talk about emotion resolutions. Families will participate in baseline, 8 week post, 6 month and 1 year follow-up assessments with a repeated measures battery of interviews, observations, and assessments of maternal and child behavioral and biological functioning. The RET intervention and physiological assessment procedures are based on extensive new pilot research. This multi-level, multi-measure approach will enable researchers to fully evaluate the efficacy of the RET intervention, and the mechanisms underlying intervention effects. Consequently, this project addresses significant societal concerns relevant to the psychological and biological health of maltreated children through the evaluation of an innovative brief intervention. As such, the study has potential to significantly advance scientific knowledge and to inform more effective clinical and policy efforts designed to improve the welfare of maltreated children and families, including programs that may be readily disseminated to communities nationally.